What is the best antibiotic for skin infections caused by Staphylococcus aureus, including Methicillin-resistant Staphylococcus aureus (MRSA)?

Best Antibiotics for Skin Infections Caused by Staphylococcus aureus, Including MRSA

For skin infections caused by Staphylococcus aureus, including MRSA, clindamycin is the preferred first-line oral antibiotic due to its effectiveness against both MRSA and β-hemolytic streptococci, with trimethoprim-sulfamethoxazole, tetracyclines, and linezolid as alternative options based on infection severity and patient factors. 1

Initial Management Approach

• Incision and drainage is the primary treatment for cutaneous abscesses, and may be adequate alone for simple abscesses without antibiotics 2
• Antibiotic therapy is recommended when abscesses are associated with:
  • Severe or extensive disease involving multiple sites 2
  • Rapid progression with associated cellulitis 2
  • Signs and symptoms of systemic illness 2
  • Associated comorbidities or immunosuppression 2
  • Extremes of age 2
  • Abscess in difficult-to-drain areas (face, hand, genitalia) 2
  • Associated septic phlebitis 2
  • Lack of response to incision and drainage alone 2

Recommended Oral Antibiotics for Outpatient Treatment

First-Line Options:

• Clindamycin (300-450 mg three times daily for adults):

  • Advantages: Covers both MRSA and β-hemolytic streptococci 1
  • Caution: Potential cross-resistance in erythromycin-resistant strains; inducible resistance in MRSA 2
  • Dosing: 300-450 mg three times daily for adults; 10-20 mg/kg/day in 3 divided doses for children 2

• Trimethoprim-sulfamethoxazole (TMP-SMX) (1-2 double-strength tablets twice daily):

  • Highly effective against MRSA 2, 3
  • Limited coverage of β-hemolytic streptococci (not recommended as single agent for non-purulent cellulitis) 2
  • Consider combining with a β-lactam (e.g., amoxicillin) if streptococcal coverage is needed 2

• Tetracyclines (doxycycline 100 mg twice daily or minocycline 100 mg twice daily):

  • Effective against MRSA 2, 4
  • Contraindicated in children under 8 years of age 2
  • Minocycline may be more effective than doxycycline for treatment failures 4

Second-Line Option:

• Linezolid (600 mg twice daily):
  • Highly effective against MRSA and streptococci 5
  • No cross-resistance with other antibiotic classes 1
  • Limitations: High cost; potential for hematologic toxicity with prolonged use 3
  • FDA-approved for complicated and uncomplicated skin infections 5

Treatment for Hospitalized Patients with Complicated Infections

For patients requiring hospitalization with complicated skin infections (deeper soft-tissue infections, surgical/traumatic wound infection, major abscesses):

• Vancomycin (IV): First-line parenteral therapy for MRSA 2
• Linezolid (600 mg IV/PO twice daily): Equivalent efficacy to vancomycin 2
• Daptomycin (4 mg/kg IV once daily): Effective for MRSA skin infections 2
• Telavancin (10 mg/kg IV once daily): Alternative for complicated infections 2

Duration of Therapy

• 5-10 days for uncomplicated skin infections, individualized based on clinical response 2, 1
• 7-14 days for complicated skin infections 2, 1

Special Populations

Pediatric Patients:

• Mupirocin 2% topical ointment for minor skin infections 2
• Clindamycin (10-13 mg/kg/dose IV every 6-8 hours or 10-20 mg/kg/day PO in 3 divided doses) 2
• Vancomycin for hospitalized children with complicated infections 2
• Linezolid (10 mg/kg/dose every 8 hours for children <12 years; 600 mg twice daily for children >12 years) 2
• Avoid tetracyclines in children under 8 years of age 2

Common Pitfalls to Avoid

• Do not use rifampin as a single agent or as adjunctive therapy for MRSA skin infections 2
• TMP-SMX should not be used as a single agent for non-purulent cellulitis due to poor streptococcal coverage 2
• For patients with purulent drainage, always obtain cultures to guide therapy 2
• Consider local resistance patterns when selecting empiric therapy 1
• Do not rely on vancomycin for outpatient oral therapy as it has poor oral bioavailability 1

Prevention of Recurrent Infections

• Keep draining wounds covered with clean, dry bandages 2
• Maintain good personal hygiene with regular bathing 2
• Avoid sharing personal items that contact skin 2
• Consider decolonization strategies for recurrent infections 2
• Focus cleaning on high-touch surfaces in household settings 2